Don’t expect anything groundbreaking from “Chimichangas and Zoloft.” Fernanda Coppel’s play may be new, but its themes are well-worn: girls coming of age, sexual identity, philandering husbands and depressed wives.

But the Mexican-American writer, only 26, brings lively energy — and a couple of nice twists — to situations we’ve seen a million times before. She treats all her characters, no matter their faults, with sympathy. And refreshingly, the show takes place in a milieu we rarely see on local stages: Mexican-American middle-class families in LA.

Here we have two of them, each with problems that end up overlapping in surprising ways.

Penelope (Xochitl Romero) is 16, and her best friend, Jackie (Carmen Zilles), is a year younger. They’re well-adjusted and sassy, with typical teen issues.

Raised by her single dad, Alejandro (Alfredo Narciso), Penelope has started having sex, and longs for a mother who could guide her through the whole complicated mess.

Jackie does have a mom, but Sonia (Zabryna Guevara) is in a funk — hence the play’s title — and has gone AWOL, temporarily leaving her husband and Jackie’s distant father, Ricardo (Teddy Canez).

The girls and their parents try to reconcile what their hearts tell them with what society dictates, but it’s not easy. Some stick to their guns, others chicken out.

Coppel keeps things moving, and she has a knack for snappy dialogue. Penelope and Jackie, who call each other “dude,” speak fluent Valley girl-ese. They’re funny and brash, even if they’re not as tough as they pretend to be.

Alejandro isn’t far behind in the one-liner department. “Sex is like buying a motorcycle,” he warns. “Sure, it looks cool and shiny. But at any turn you could crash into a taco truck and die.”

And when Penelope tells him that her drug-dealing boyfriend “sells herbal remedies,” Alejandro shoots back, “Are you dating a shaman?”

Less convincing are Sonia’s occasional monologues. They don’t connect well with the rest of the show, and at times it feels as if we’re watching two separate plays grafted together.

Still, it only seems like youthful fumbling on the part of a promising new voice.